With the advent of the U.S. involvement in World War II, Harris' group began advising
the Army Quartermaster about textiles, as well as helping to solve a myriad of problems
for the National Bureau of Standards. George Dorio, a Frenchman from the Harvard Business
School, was recruited to run the Research and Development Branch of the Office of
the Quartermaster General. According to Harris, Colonel Dorio called him one Sunday
morning and immediately requested his presence at the Pentagon. Upon Harris' arrival,
Colonel Dorio pulled out some cotton underwear from a box. Almost immediately the
underwear disintegrated. Colonel Dorio wanted to know why this had occurred. They
soon found out that the cotton which comprised the garment had been treated with chemicals
against gas warfare, and in the process hydrochloric acid had been liberated which
led to the deterioration of the fabric. Since Harris had already been working on the
degradation of cellulose by various methods, Dorio had him start work on this new
project the next day.

Another military stumbling block that Harris' group worked on was the development
of a shrink-proofing process to alleviate the difficulty of laundering soldier's uniforms
in the field. They also made great strides in the prevention of rotting sandbag and
tent materials, as well as determining why electrical equipment kept shorting out
in the South Pacific. The importance of shrink-proofing is evident in that, simply
from not having to replace items such as socks and underwear, the Army saved approximately
$1,500,000 per month during World War II. Harris also studied the dispersal of water
vapor through fabric, and determined that water vapor passed through tightly woven
and loosely woven clothing with equal rapidity, neglecting appreciable wind. With
this information in hand, tropical uniforms of soldiers were redesigned with thin,
tightly woven material, greatly improving the efficiency and morale of the soldiers.